PubMed Health⌕ Search

Biomedical subjects

J Nunez

Publications and source records attributed to J Nunez.

At least 19 recordsLinked to original sources
PubMed2005

Regionalization of epididymal duct and epithelium in rats and mice by automatic computer-aided morphometric analysis.

AIM: To establish a rat and mouse epididymal map based on the use of the Epiquatre automatic software for histologic image analysis. METHODS: Epididymides from five adult rats and five adult mice were fixed in alcoholic Bouin's fixative and embedded in paraffin. Serial longitudinal sections through the medial aspect of the organ were cut at 10 microm and stained with hematoxylin and eosin. As determined from major connective tissue septa, nine subdivisions of the rat epididymis and seven for the mouse were determined, consisting of five sub-regions in the caput (rat and mouse), one (mouse) or three (rat) in the corpus and one in the cauda (rat and mouse). Using the Epiquatre software, several tubular, luminal and epithelial morphometric parameters were evaluated. RESULTS: Statistical comparison of the quantitative parameters revealed regional differences (2-5 in the rat, 3-6 in the mouse, dependent on parameters) with caput regions 1 and 2 being largely distinguishable from the similar remaining caput and corpus, which were in turn recognizable from the cauda regions in both species. CONCLUSION: The use of the Epiquatre software allowed us to establish regression curves for different morphometric parameters that can permit the detection of changes in their values under different pathological or experimental conditions.

Animals↗
PubMed2004

Dynamic light scattering in liquid and supercooled diphenylmethane.

We use a dynamic light scattering technique to measure both polarized (VV) and depolarized (VH) spectra of liquid diphenylmethane (DPM) between 288 and 362 K, covering both normal and supercooled liquid ranges. Our results allow extracting information on structural relaxation processes, rotational motions, rotation-translation couplings, and molecular reorientation phenomena in liquid DPM. The VV spectra are modeled according to the microscopic theory of Wang, which assumes that a structural relaxation process dominates the spectrum. We find that the relaxation time of the structural relaxation in DPM follows an Arrhenius behavior. The Rayleigh dip was observed in the VH spectra, which are described using the Andersen-Pecora theory. Our results are discussed in terms of the rotation-translation coupling parameter, which we find independent of temperature over the experimental range. The collective reorientation time also follows an Arrhenius behavior with temperature. Finally, we calculate the hydrodynamic volumes for the reorientation process from geometric molecular models in two hydrodynamic limits: slip and stick boundary conditions. Our results suggest that the DMP molecule reorientates in quasi-slipping conditions in the bulk liquid.

Journal Article↗
PubMed2002

A childhood malignant rhabdoid tumour of the kidney.

A case report is presented of a malignant rhabdoid tumour occurring in the kidney of a 23-month-old boy. Important differences between this and the conventional Wilms' tumour include the histological demonstration of sheets or cords of large cells resembling myoblasts, a tendency to frequent clinical relapse, and a high mortality rate despite multimodal therapy. In this child, an encouraging initial response to pre-operative chemotherapy, followed by surgical excision and postoperative triple chemotherapy, was not sustained. Recurrence of pulmonary metastases did not respond to further chemotherapy and whole lung irradiation.

Humans↗
PubMed2001

Brain glucose utilization in mice with a targeted mutation in the thyroid hormone alpha or beta receptor gene.

Brain glucose utilization is markedly depressed in adult rats made cretinous after birth. To ascertain which subtype of thyroid hormone (TH) receptors, TRalpha1 or TRbeta, is involved in the regulation of glucose utilization during brain development, we used the 2-[(14)C]deoxyglucose method in mice with a mutation in either their TRalpha or TRbeta gene. A C insertion produced a frameshift mutation in their carboxyl terminus. These mutants lacked TH binding and transactivation activities and exhibited potent dominant negative activity. Glucose utilization in the homozygous TRbetaPV mutant mice and their wild-type siblings was almost identical in 19 brain regions, whereas it was markedly reduced in all brain regions of the heterozygous TRalpha1PV mice. These suggest that the alpha1 receptor mediates the TH effects in brain. Inasmuch as local cerebral glucose utilization is closely related to local synaptic activity, we also examined which thyroid hormone receptor is involved in the expression of synaptotagmin-related gene 1 (Srg1), a TH-positively regulated gene involved in the formation and function of synapses [Thompson, C. C. (1996) J. Neurosci. 16, 7832-7840]. Northern analysis showed that Srg1 expression was markedly reduced in the cerebellum of TRalpha(PV/+) mice but not TRbeta(PV/PV) mice. These results show that the same receptor, TRalpha1, is involved in the regulation by TH of both glucose utilization and Srg1 expression.

Age Factors↗
PubMed2000

Chemokine and chemokine-receptor expression in human glial elements: induction by the HIV protein, Tat, and chemokine autoregulation.

Human immunodeficiency virus (HIV) encephalitis is a prominent pathology seen in children infected with HIV. Immunohistochemical analyses of pediatric brain tissue showed distinct differences in expression of C-C chemokines and their receptors between children with HIV encephalitis and those with non-CNS-related pathologies. Evidence suggests that soluble factors such as HIV Tat released from HIV-infected cells may have pathogenic effects. Our results show Tat effects on chemokines and their receptors in microglia and astrocytes as well as chemokine autoregulation in these cells. These results provide evidence for the complex interplay of Tat, chemokines, and chemokine receptors in the inflammatory processes of HIV encephalitis and illustrate an important new role for chemokines as autocrine regulators.

Adolescent↗
PubMed1998

Timing of removal of the laryngeal mask airway.

Previous studies reported that complications associated with removal of the laryngeal mask were more frequent in awake patients than in anaesthetised patients; however, these studies did not comply with the method described in the manufacturer's instruction manual. The reported incidences of regurgitation during the use of the laryngeal mask also differ considerably between studies. We studied these factors in 66 patients in whom the method described in the manual was used. After induction of anaesthesia, the laryngeal mask and a pH probe were inserted and the cuff of the mask was inflated with a minimum volume of air. Anaesthesia was maintained with nitrous oxide and isoflurane in oxygen. At the end of the operation, we randomly allocated patients to one of two groups and the laryngeal mask was removed either while they were still deeply anaesthetised or after they had regained consciousness. No apparent regurgitation occurred in any patient during operation, but one patient in the anaesthetised group regurgitated immediately after removal of the mask. The incidence of complications during or after removal of the laryngeal mask was significantly greater in the anaesthetised group than that in the awake group (p << 0.001; difference [95% CI]: 48.5 [30.5-66.5]%). Therefore, the laryngeal mask can be safely left in place until the patient has regained consciousness after emergence from anaesthesia.

Adolescent↗
PubMed1997

Microtubule-associated proteins (MAPs) in the peripheral nervous system during development and regeneration.

In this article, we have described the structure and distribution of the various variants of the microtubule-associated proteins (MAPs), tau, MAP2, MAP1A, and MAP1B, that are expressed in the dorsal root ganglion (DRG) and spinal cord during development and regeneration. We have summarized the data on their gene structure and compared the sequence of the major transcripts encoding these MAPs that are expressed in the brain, the spinal cord, and the DRG. Finally, we have surveyed the studies that used a variety of experimental approaches (e.g., antisense inhibition, transgenic knockouts, and expression in neuronal and nonneuronal cells) to understand the functional significance of MAPs heterogeneity and differences observed between the central nervous system (CNS) and the peripheral nervous system (PNS) both during development and regeneration.

Alternative Splicing↗
PubMed1996

New forms of HMW MAP2 are preferentially expressed in the spinal cord.

The high molecular weight forms of microtubule-associated protein 2 (MAP2a and b) play a central role in the specification of dendrites. RT-PCR amplification of a portion of the N-terminal and middle MAP2b domains of rat spinal cord cDNAs allowed identification of new variants containing both exon 8 (246 bp) and a new exon, 7A (237 bp), located at the beginning of the middle MAP2b region. The brain and the spinal cord express transcripts containing exon 8, whereas exon 7A alone or exons 7A+8 were detected, whatever the developmental stage, only in the spinal cord.

Amino Acid Sequence↗
PubMed1996

Four repeat high-mol-wt MAP2 forms in rat dorsal root ganglia.

The high-mol-wt forms of brain microtubule-associated protein 2 (MAP2a/b) segregate within the dendrites during neuronal differentiation, whereas a low-mol-wt variant, MAP2c, is distributed within all the neuronal domains. Both MAP2b and MAP2c contain three tubulin binding repeats, whereas another low-mol-wt form, MAP2d, contains four repeats. Since high-mol-wt MAP2 species with four repeats have been cloned so far only from the sensory ND cell line, we have studied in this work the high-mol-wt forms expressed by dorsal root ganglia (DRG). Different clones obtained from PCR amplification products of portions of the C-terminal and of the 3' end of the middle MAP2b domains contained either three or four tubulin binding repeats at adult stages and only three postnatally. In adulthood, two exons located at the 3' end of the MAP2b middle domain were missing in several clones: exon 10 within clones with three or four repeats, exon 11 only within those containing four repeats. Several other clones obtained from PCR amplification products of portions of the N-terminal and of the 5' end of the middle MAP2b domains revealed exons 7A and 8. In contrast, Northern analysis revealed exon 8 but not exon 7A, which is probably expressed in trace amounts in the DRG. In this article, we have identified for the first time high-mol-wt MAP2 transcripts containing four tubulin binding repeats that seem to be expressed only by the DRG and also differing from brain MAP2b by a number of other exons.

Aging↗
PubMed1996

Jaw thrusting as a clinical test to assess the adequate depth of anaesthesia for insertion of the laryngeal mask.

We have studied the efficacy of the loss of response to jaw thrust as a clinical test to assess adequate depth of anaesthesia for insertion of the laryngeal mask in 60 patients. After induction of anaesthesia with propofol (infused using a syringe driver), the patients were randomly allocated to one of two groups. In one group, insertion of the laryngeal mask was attempted immediately after the loss of verbal contact and in the other group, after the loss of motor response to a jaw thrust. Conditions for insertion of the laryngeal mask were assessed. The mean dose of propofol required to obtain loss of verbal contact was 1.94 mg.kg-1 (SD 0.39, 95% confidence intervals (CI) 1.79-2.08 mg.kg-1) and that for the loss of response to jaw thrust was 2.55 mg.kg-1 (SD 0.46, 95% CI 2.38-2.72 mg.kg-1). When depth of anaesthesia was assessed using jaw thrusting, it was always possible to insert the mask and the conditions were optimal in 87% (95% CI 72-95%) of patients. Neither coughing nor gagging occurred. In contrast, conditions were almost always less than optimal when insertion was attempted after the loss of verbal contact. Conditions were significantly better when jaw thrust was used as a clinical test compared with loss of verbal contact (p < < 0.001). No marked haemodynamic depression occurred in any patient. Thus, jaw thrust is a reliable clinical test to assess the adequate depth of anaesthesia for uncomplicated insertion of the laryngeal mask after induction of anaesthesia with propofol.

Adult↗
PubMed1995

Tau and microtubule-associated protein 2c transfection and neurite outgrowth in ND 7/23 cells.

Neuronal hybrid ND 7/23 cells, which display sensorylike properties, develop neurites when cultured in the presence of either dibutyryl cyclic AMP plus nerve growth factor (DBcAMP + NGF) or retinoic acid or a phorbol ester derivative, although they express only trace amounts of the microtubule-associated tau proteins and low levels of microtubule-associated protein 2c (MAP2c). Nondifferentiated ND cells transfected with tau cDNAs did not develop neurites, whereas very short cell processes were formed in MAP2c-transfected cells. tau and MAP2 antibodies labeled microtubule bundles displayed in a ring array underneath the surface of the transfected cells and short microtubules starting from the cell center. After differentiation in the presence of DBcAMP + NGF, the same bundle organization was observed in the transfected cells. In addition, tau and MAP2 antibodies stained a short section of the formed neurites. These data demonstrate that the expression of tau protein is not sufficient to induce neurite extension and that other proteins induced by morphogens are more important to initiate morphological differentiation of this cell line.

Animals↗
PubMed1995

Tumor necrosis factor receptors in neuroblastoma SKNBE cells and their regulation by retinoic acid.

The human neuroblastoma cell line SKNBE can be differentiated either by serum removal or by adding to the culture medium different morphogens, for instance, retinoic acid (RA), cyclic AMP derivatives, and phorbol esters. Both the differentiated and undifferentiated cells express the two types of membrane tumor necrosis factor (TNF) receptors (TNFRs) of 55 and 75 kDa (p55 and p75 TNFR, respectively) and also their soluble forms. After RA addition the number of the surface TNFRs per cell is increased approximately twofold, but the kinetics of expression are different, depending on the receptor type. The level of the mRNAs of 2.4 and 4.2 kb, which, respectively, encode the p55 and p75 TNFRs, is also increased during the time course of differentiation, and the kinetics of their expression are biphasic. In contrast, the number of TNFRs and the level of their encoding mRNAs remain unchanged after exposure of the cells to both a phorbol and a cyclic AMP derivative.

Blood Physiological Phenomena↗
PubMed1995

Thyroid hormones and brain development.

Thyroid hormone is a major physiological regulator of mammalian brain development. Cell differentiation, migration and gene expression are altered as a consequence of thyroid hormone deficiency or excess. The physiological role of thyroid hormone can perhaps be defined so as to ensure the timed coordination of different developmental events through specific effects on the rate of cell differentiation and gene expression. All triiodothyronine (T3) receptor isoforms are expressed in the brain and their spatial and temporal patterns of expression suggest unique and complementary functions for the different isoforms. Cell biology studies suggest a role for T3 and its receptors in oligodendroglial and neuronal differentiation and the control of cell death. Some of the effects on neuronal differentiation might be due to an action of thyroid hormone on the production of neurotropins and their receptors. In recent years a number of T3-dependent genes have been identified in the rat brain, such as myelin protein-encoding genes or specific neuronal genes, and thyroid hormone-responsive elements have been demonstrated in some of these genes. The identification of the gene network regulated by thyroid hormone during brain development, the elucidation of the mechanism of regulation and the clarification of the physiological roles of the regulated genes remain major goals for future studies.

Animals↗
PubMed1995

Identification of a new exon of the brain microtubule-associated protein 2.

The 5'-region of the transcripts encoding the HMW-(MAP2b) and LMW-(MAP2c) microtubule associated proteins in the brain was amplified by RT-PCR. The sequencing of cloned PCR fragments allowed to identify a new variant of brain HMW-MAP2 which contained, compared to MAP2b, an insertion of 246 bp located downstream the 5'-junction between MAP2b and MAP2c and that does not alter the open reading frame of MAP2b. The number of amino acid residues encoded by this insertion increases the molecular weight by 8.5 kDa i.e. corresponds to the difference in apparent size between MAP2a and MAP2b. A LMW-MAP2 PCR amplification product containing this insertion has been also identified. Genomic Southern blot analysis confirmed that this region belongs to the MAP2 gene and is located on a single exon.

Amino Acid Sequence↗
PubMed1994

Two novel HMW MAP2 variants with four microtubule-binding repeats and different projection domains.

The brain microtubule-associated protein MAP2 is composed of two high molecular (MAP2a and b) and one low molecular (MAP2c) weight isoforms. All these forms were thought to contain three repeated microtubule-binding domains in their C-terminal region but a MAP2c variant containing four repeats has recently been identified. We report here the existence of two high molecular weight MAP2 isoforms with four microtubule-binding domains in the sensory neuronal cell line ND 7/23. A stretch of 135 bp is missing in one of these forms suggesting that several HMW MAP2 variants can be produced by alternative splicing.

Alternative Splicing↗
PubMed1994

Tear lactoferrin levels and ocular bacterial flora in HIV positive patients.

Keratoconjunctivitis Sicca(4) has recently been reported to occur at a greater rate in HIV-positive symptomatic patients. We looked at HIV positive asymptomatic patients, compared to age matched HIV negative patients to study external ocular resistant factors, namely lactoferrin levels in tears, bacterial flora in lid margins, conjunctiva and tears, and evidence of dry eyes using a Schirmer test and tear osmolarity. Eighteen eyes of nine HIV positive patients and eighteen eyes of HIV negative controls were studied. Results showed markedly decreased lactoferrin levels in HIV positive asymptomatic patients with a mean of 85.8 mgs/dcl compared to HIV negative patients with a mean 156 mgs/dcl (P < 0.01). There were increased numbers of colonies of bacterial flora on the lids of HIV positive asymptomatic patients with an average colony count 4.1 colonies/patient compared to 1.5 colonies/patients in the control group (P < 0.025). Seventy eight percent of the study group had bacterial growth compared to 33% in the control group. The tear osmolarity in both groups had no significant difference; mean in HIV positive being 312 mosml/litre; mean in control 306 mosml/litre. The Schirmer test also showed no significant difference, with the mean in HIV positive patients being 11 mm wetting, and in control patients being 12.7 mm wetting. Therefore, despite no symptomatic or clinical evidence of dry eyes, asymptomatic HIV-positive patients had markedly decreased levels of lactoferrin in tears and increased colony counts of bacterial flora in the lids.

Acquired Immunodeficiency Syndrome↗